—w-——K————r— sm 
EXPLORATIONS FROM A. D. 1843 TO A p. 1852. 41 
(between the points named) in 1843, and is an excellent map for travellers. It is not, however, 
accurately constructed, according to the list of geographical positions given in Captain 
Frémont’s report, and this should be borne in mind by compilers. 
Throughout this iğtlioned E رود‎ in the mountains and across the wry Lieutenant 
Frémont made many ast observations, determining longitude by observing occulta- 
tions and eclipses with a telescope and by chronometric differences, and latitudes by observing 
with sextants and artificial horizons. After the investigations necessary in compiling the map 
which accompanies this memoir, I may be permitted to add my testimony to the truth of 
Captain Frémont’s assertion in his notice to the reader at the beginning of his report, 
“that the correctness of the longitudes and latitudes may well be relied upon." They contain 
only such errors of longitude as are inherent to results obtained from observations made with 
the instruments employed. A mercurial barometer was carried across the continent on the 
road to Oregon as far as the Blue mountains, where it was broken. The subsequent elevations 
on the route were determined by the temperature of boiling water. __ 
^ The second expedition under Lieutenant Frémont left the town of Kansas on the: 29th of 
May, 1843. The party consisted of twenty-nine men, all mounted, their stores, &c., being 
carried in twelve carts. He was assisted by Mr. Charles Preuss as topographer, Mr. Thomas 
Fitzpatrick as guide, and Mr. Theodore Talbot. The party proceeded up the Kansas river to 
the junction of the Smoky Hill and Republican — and thence " the latter stream to a 
point about 270 miles from where they started. — 
Here Lieutenant Frémont divided his party, taking Mr. Preuss and a few men with him, 
and leaving the carts in charge of Mr. Fitzpatrick. The party under Lieutenant Frémont 
proceeded rapidly in advance, left the valley of the main stream, and keeping on the divide, 
between it and Soloman’s Fork, continued their westward course. This brought them again to 
the Republican Fork, which they now crossed, passed the dividing ridge between it and the 
South fork of the Platte, and travelled up the valley of the latter to St. Vrain’s Fort. Leaving 
this point, the party proceeded up the valley of the South fork of the Platte to where it issues 
from the mountains. Here they struck toward the east, crossing the sources of several tribu- 
taries of the South fork, one of which, Bijou creek, they followed to its source. From this 
point they travelled mana to Boiling Spring creek, and down this stream to its junction 
with the Arkansas. - at Frémont returned again to St. Vrain's Fort by the direct route 
up Boiling Spring seis and was there joined by the party under Mr. Fitzpatrick.  — 
The while: party now ascended the valley of the Cache à la Poudre creek, Mito tough 
the Black Hills by the narrow, rocky valley of that stream; thence over a rolling open country 
they wound around the north side of the Medicine Bow mountains, and passing by a rough 
road through the Medicine Bow Butte Pass, descended to the north fork of the Platte. Crossing 
this stream they attempted to take a direct route for the South Pass over the high plateau 
constituting the dividing ridge between the Atlantic and Pacific waters, but finding the country 
hilly, barren, and uninteresting, they turned northward to the valley of the Sweetwater river. 
Striking this stream twenty miles above Devil’s Gate, they travelled up its valley to the South 
Pass, turned to the southwest, and followed the emigrant road to Oregon, along the course of 
the Big Sandy to its mouth. Crossing Green river, (the main branch of the Great Colorado of 
the west,) and reaching Black’s Fork, about thirty-five miles above its junction with Green 
river, they travelled up its valley to near Bridger’s Fort. Passing over a low ridge to the 
north, called by the trappers ‘‘Little Mountain,’’ they now descended to one of the sources of 
